CA2674263A1 - Method for determination of resonant frequencies of a rotor using magnetic bearings - Google Patents
Method for determination of resonant frequencies of a rotor using magnetic bearings Download PDFInfo
- Publication number
- CA2674263A1 CA2674263A1 CA002674263A CA2674263A CA2674263A1 CA 2674263 A1 CA2674263 A1 CA 2674263A1 CA 002674263 A CA002674263 A CA 002674263A CA 2674263 A CA2674263 A CA 2674263A CA 2674263 A1 CA2674263 A1 CA 2674263A1
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- frequency
- oscillations
- frequencies
- resonant frequencies
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 19
- 238000000034 method Methods 0.000 title claims abstract description 16
- 230000010355 oscillation Effects 0.000 claims abstract description 18
- 230000010358 mechanical oscillation Effects 0.000 claims abstract description 7
- 238000001228 spectrum Methods 0.000 claims description 4
- 239000000306 component Substances 0.000 description 3
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C32/00—Bearings not otherwise provided for
- F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
- F16C32/0406—Magnetic bearings
- F16C32/044—Active magnetic bearings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D19/00—Axial-flow pumps
- F04D19/02—Multi-stage pumps
- F04D19/04—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps
- F04D19/048—Multi-stage pumps specially adapted to the production of a high vacuum, e.g. molecular pumps comprising magnetic bearings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
- F04D27/001—Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C32/00—Bearings not otherwise provided for
- F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C39/00—Relieving load on bearings
- F16C39/06—Relieving load on bearings using magnetic means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H13/00—Measuring resonant frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
- G01M13/04—Bearings
- G01M13/045—Acoustic or vibration analysis
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
- H02K7/08—Structural association with bearings
- H02K7/09—Structural association with bearings with magnetic bearings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2360/00—Engines or pumps
- F16C2360/44—Centrifugal pumps
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2360/00—Engines or pumps
- F16C2360/44—Centrifugal pumps
- F16C2360/45—Turbo-molecular pumps
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Acoustics & Sound (AREA)
- Non-Positive Displacement Air Blowers (AREA)
- Magnetic Bearings And Hydrostatic Bearings (AREA)
Abstract
The invention relates to a method for determination of resonant frequencies of a rotor using magnetic bearings, in particular of a rotor of a turbomolecular vacuum pump. While the rotor is stationary or the rotor is rotating at a relatively low rotation frequency, mechanical oscillations of the rotor are generated by electromagnets in the magnetic bearing. The rotor oscillations are detected by rotor-position sensors in the magnetic bearing. The resonant frequencies of the rotor are determined from the detected rotor-position oscillations.
Description
Method for Determination of Resonant Frequencies of a Rotor Using Magnetic Bearings The invention refers to a method for the determination of resonant frequencies of a rotor supported by an active magnetic bearing.
Because of their frictionless nature, machines with a magnetically levitated rotor are generally fast rotating machines, such as turbomolecular vacuum pumps. In all applications, but especially with high-speed rotors, the rotational frequency of the rotor must be controlled such that the critical natural fre-quency of the rotor, i.e. the so-called resonant frequency, possibly does not at all coincide with the rotational frequency or does so only as shortly as possible so as to avoid or minimize resonance and to thereby avoid mechanical over-straining of the rotor.
In addition, the gap between the pump rotor and the pump stator in turbo-molecular vacuum pumps is extremely small to keep the back-leakage conduc-tance at a minimum. Excessive deflections of the pump rotor that might result in a collision with the pump stator must be avoided at any rate. For this rea-son, it should be avoided to operate a magnetically levitated turbomolecular pump near the resonant frequency of the rotor.
With rotors or turbomolecular vacuum pumps of the prior art, the resonant frequencies for each model are determined by experiments and the control or regulation of the rotational speed of the pumps of a respective model are rig-idly set such that the rotor resonant frequencies are avoided or are swept as fast as possible during the power up or power down. Due to the specimen-related variation within a model and possible changes over the entire opera-tion cycle, comparatively large safety margins should be provided around an experimentally determined resonant frequency of a model.
In view of this, it is an object of the invention to provide a method with which the resonant frequencies of a magnetically levitated rotor can always be de-termined precisely.
This object is achieved, according to the invention, with a method having the features of claim 1.
The method of the invention is exclusively directed to a magnetically levitated rotor as it is frequently used in particular in turbomolecular vacuum pumps.
During a rotor standstill or when the rotor rotates at a frequency not too close to the rated rotational frequency of the rotor, the electromagnets of the mag-netic bearing of the rotor generate mechanical oscillations of the rotor. At the same time, rotor-position sensors of the magnetic bearing detect or sense the generated rotor oscillations. From the oscillations detected and the information about the frequency of the generated oscillations, the resonant frequencies of the rotor can be determined.
The resonant frequencies of the rotor are thus determined at rotational fre-quencies of the rotor that do not induce a mechanical resonance of the rotor.
The determination of the resonance frequencies described can be performed while the rotor is stationary. However, the determination of the resonant fre-quencies is more precise when the rotor is rotating slowly, since the resonance frequency of the rotor changes with its dynamic load during rotation.
Preferably, the frequencies of the generated oscillations range at least partly above the rotational frequency of the rotor. In other words: by generating me-chanical rotor oscillations by the magnetic bearing, the rotor need not be ex-cited rotationally in order to be able to determine its resonant frequencies.
However, the higher the rotational frequency of the rotor is during the deter-mination of the resonant frequencies of the rotor, the more accurate the reso-nant frequency can be determined. On the other hand, the rotational fre-quency of the rotor should be as low as possible during the determination of the resonant frequency, so as to reduce the risk of collision and to limit the damage in the event of a collision. Moreover, the determination of the reso-nant frequency at low rotational frequencies of the rotor or at standstill allows for a quick determination of the resonant frequencies since a protracted in-crease of the rotational frequency of the rotor can be omitted or takes but lit-tle time. The actual determination of the resonant frequencies of the rotor may possibly be done within a few seconds.
According to a preferred embodiment, during the generation of the oscilla-tions, the rotational frequency of the rotor is less than 70% of the rated rota-tional frequency of the rotor and it is particularly preferred to be less than 30%. Tests have shown that rotational frequencies of the rotor of 10% of the rated rotational frequency of the rotor already allow for a determination of the resonant frequencies of the rotor with a sufficiently high accuracy.
The exact determination of the resonant frequencies of the rotor makes it pos-sible to select a rated rotational frequency of the rotor even between two resonant frequencies of the rotor. The exact item-related determination of the resonant frequency allows to determine frequency bands for the operation of the rotor, which without a precise knowledge of the resonant frequency could possibly not be used because of the safety margins required in this case.
Compared to using resonant frequencies that are first determined with refer-ence to a model and are then fixedly stored in all items of a model, the pre-sent method is advantageous in that it allows to determine resonant frequen-cies individually for each single rotor. Since the resonant frequencies deter-mined for each single rotor are individually known, the rotor can generally be driven at rotational frequencies closer to the individual resonant frequencies of the rotor, since no corresponding safety margins have to be provided for variations as they would have to be provided for fixedly programmed resonant frequencies. Especially with turbomolecular vacuum pumps, it has been found that significant item-related variations of the critical resonant frequencies can `-1' be determined from one item of a model to the next so that knowing the ac-tual rotor-related resonant frequencies offers great advantages.
Determining the resonant frequencies with the method described can be per-formed upon the first start-up of the machine having the rotor, but may alter-natively or additionally be done at regular intervals or after longer periods of standstill.
Preferably, the electromagnets of the magnet bearing generate mechanical oscillations of different oscillation frequencies. For instance, it is possible to generate oscillations of the entire rotational frequency spectrum in which the respective machine or the respective rotor is to be used. The frequency spec-trum intended to be generated in the rotor by the electromagnets of the mag-netic bearing may, however, be restricted to the critical ranges known and typical for the respective model of the machine or the rotor.
In a preferred embodiment, the method refers to the determination of reso-nant frequencies of a magnetically levitated rotor of a turbomolecular vacuum pump. In such a machine, the gaps between the pump rotor and the pump stator are extremely small so that operating the rotor at or near its resonant frequency entails a significant risk of collision. When using fixedly programmed model-specific resonant frequencies of a rotor, substantial safety margins have to be taken into account because of item variations. By determining the reso-nant frequencies for a respective rotor or a respective vacuum pump, these safety margins can be selected a lot narrower so that the turbomolecular vac-uum pump can be operated at rotational frequencies that are much closer to the resonant frequency than would be the case with fixedly programmed model-specific resonant frequencies.
An embodiment of the invention will be detailed hereunder.
The invention will be explained in detail with reference to a turbomolecular vacuum pump. Among others, the rotor of a turbomolecular vacuum pump consists of a shaft on which a motor rotor and a pump rotor are rigidly mounted. Further, the shaft may be provided with rotor-side components of the magnet bearing, for instance, permanent magnetic sleeves, rings, etc.
On the stator side, a pump stator, a motor stator and stator-side components of the magnet bearing are provided among others. The stator-side compo-nents of the magnetic bearing include, among others, a plurality of electro-magnets controlled by a magnet bearing control. Moreover, rotor-position sen-sors are provided on the stator side that are adapted to determine the exact position of the rotor at a high measuring frequency and with high accuracy.
When the rotor is at a standstill, a stationary test run is performed prior to the first start-up as well as at regular intervals before powering the rotor up to its operating rotational frequency. Here, the electromagnets of the magnetic bearing maintain the rotor in a floating operating position and is subjected to mechanical oscillations. Thus, the magnetic bearing generates rotor oscilla-tions over a frequency spectrum in which a resonant frequency or a plurality of resonant frequencies specific to the structure or the model of the vacuum pump are expected.
The rotor-position sensors determine whether the rotor oscillations of the re-spective oscillation frequency generated by the electromagnets of the mag-netic bearing build up or not.
In this manner, the resonant frequency of the rotor, which may also change over the operation cycle, can be determined at any time with high accuracy.
For the operation of the rotor, relatively narrow frequency bands can be pro-vided as a safety margin around the detected resonant frequency of the rotor.
The rotor or the turbomolecular vacuum pump can thus be operated at rota-tional frequencies which are, if desired, relative close to a resonant frequency determined in this manner. To be able to operate the turbomolecular vacuum pump in the supercritical rotational frequency range, i.e. in a rotational fre-quency range above a resonant frequency, the region around the resonant frequency must be swept as quickly as possible. Also for the powering up of a vacuum pump to a supercritical rotational speed frequency, an exact informa-tion about the resonant frequency of the rotor is of great importance.
Possibly, the maximum rotational frequency can be selected as close as possi-ble below the resonant frequency of the rotor. The exact determination of the resonant frequency allows to select an operating rotational frequency that may be higher than and thus closer to a resonant frequency than would be possible if the item variation of the resonant frequency were not known. Thus, the maximum rotational frequency of a turbomolecular vacuum pump can be in-creased by up to 10% - 15%.
Because of their frictionless nature, machines with a magnetically levitated rotor are generally fast rotating machines, such as turbomolecular vacuum pumps. In all applications, but especially with high-speed rotors, the rotational frequency of the rotor must be controlled such that the critical natural fre-quency of the rotor, i.e. the so-called resonant frequency, possibly does not at all coincide with the rotational frequency or does so only as shortly as possible so as to avoid or minimize resonance and to thereby avoid mechanical over-straining of the rotor.
In addition, the gap between the pump rotor and the pump stator in turbo-molecular vacuum pumps is extremely small to keep the back-leakage conduc-tance at a minimum. Excessive deflections of the pump rotor that might result in a collision with the pump stator must be avoided at any rate. For this rea-son, it should be avoided to operate a magnetically levitated turbomolecular pump near the resonant frequency of the rotor.
With rotors or turbomolecular vacuum pumps of the prior art, the resonant frequencies for each model are determined by experiments and the control or regulation of the rotational speed of the pumps of a respective model are rig-idly set such that the rotor resonant frequencies are avoided or are swept as fast as possible during the power up or power down. Due to the specimen-related variation within a model and possible changes over the entire opera-tion cycle, comparatively large safety margins should be provided around an experimentally determined resonant frequency of a model.
In view of this, it is an object of the invention to provide a method with which the resonant frequencies of a magnetically levitated rotor can always be de-termined precisely.
This object is achieved, according to the invention, with a method having the features of claim 1.
The method of the invention is exclusively directed to a magnetically levitated rotor as it is frequently used in particular in turbomolecular vacuum pumps.
During a rotor standstill or when the rotor rotates at a frequency not too close to the rated rotational frequency of the rotor, the electromagnets of the mag-netic bearing of the rotor generate mechanical oscillations of the rotor. At the same time, rotor-position sensors of the magnetic bearing detect or sense the generated rotor oscillations. From the oscillations detected and the information about the frequency of the generated oscillations, the resonant frequencies of the rotor can be determined.
The resonant frequencies of the rotor are thus determined at rotational fre-quencies of the rotor that do not induce a mechanical resonance of the rotor.
The determination of the resonance frequencies described can be performed while the rotor is stationary. However, the determination of the resonant fre-quencies is more precise when the rotor is rotating slowly, since the resonance frequency of the rotor changes with its dynamic load during rotation.
Preferably, the frequencies of the generated oscillations range at least partly above the rotational frequency of the rotor. In other words: by generating me-chanical rotor oscillations by the magnetic bearing, the rotor need not be ex-cited rotationally in order to be able to determine its resonant frequencies.
However, the higher the rotational frequency of the rotor is during the deter-mination of the resonant frequencies of the rotor, the more accurate the reso-nant frequency can be determined. On the other hand, the rotational fre-quency of the rotor should be as low as possible during the determination of the resonant frequency, so as to reduce the risk of collision and to limit the damage in the event of a collision. Moreover, the determination of the reso-nant frequency at low rotational frequencies of the rotor or at standstill allows for a quick determination of the resonant frequencies since a protracted in-crease of the rotational frequency of the rotor can be omitted or takes but lit-tle time. The actual determination of the resonant frequencies of the rotor may possibly be done within a few seconds.
According to a preferred embodiment, during the generation of the oscilla-tions, the rotational frequency of the rotor is less than 70% of the rated rota-tional frequency of the rotor and it is particularly preferred to be less than 30%. Tests have shown that rotational frequencies of the rotor of 10% of the rated rotational frequency of the rotor already allow for a determination of the resonant frequencies of the rotor with a sufficiently high accuracy.
The exact determination of the resonant frequencies of the rotor makes it pos-sible to select a rated rotational frequency of the rotor even between two resonant frequencies of the rotor. The exact item-related determination of the resonant frequency allows to determine frequency bands for the operation of the rotor, which without a precise knowledge of the resonant frequency could possibly not be used because of the safety margins required in this case.
Compared to using resonant frequencies that are first determined with refer-ence to a model and are then fixedly stored in all items of a model, the pre-sent method is advantageous in that it allows to determine resonant frequen-cies individually for each single rotor. Since the resonant frequencies deter-mined for each single rotor are individually known, the rotor can generally be driven at rotational frequencies closer to the individual resonant frequencies of the rotor, since no corresponding safety margins have to be provided for variations as they would have to be provided for fixedly programmed resonant frequencies. Especially with turbomolecular vacuum pumps, it has been found that significant item-related variations of the critical resonant frequencies can `-1' be determined from one item of a model to the next so that knowing the ac-tual rotor-related resonant frequencies offers great advantages.
Determining the resonant frequencies with the method described can be per-formed upon the first start-up of the machine having the rotor, but may alter-natively or additionally be done at regular intervals or after longer periods of standstill.
Preferably, the electromagnets of the magnet bearing generate mechanical oscillations of different oscillation frequencies. For instance, it is possible to generate oscillations of the entire rotational frequency spectrum in which the respective machine or the respective rotor is to be used. The frequency spec-trum intended to be generated in the rotor by the electromagnets of the mag-netic bearing may, however, be restricted to the critical ranges known and typical for the respective model of the machine or the rotor.
In a preferred embodiment, the method refers to the determination of reso-nant frequencies of a magnetically levitated rotor of a turbomolecular vacuum pump. In such a machine, the gaps between the pump rotor and the pump stator are extremely small so that operating the rotor at or near its resonant frequency entails a significant risk of collision. When using fixedly programmed model-specific resonant frequencies of a rotor, substantial safety margins have to be taken into account because of item variations. By determining the reso-nant frequencies for a respective rotor or a respective vacuum pump, these safety margins can be selected a lot narrower so that the turbomolecular vac-uum pump can be operated at rotational frequencies that are much closer to the resonant frequency than would be the case with fixedly programmed model-specific resonant frequencies.
An embodiment of the invention will be detailed hereunder.
The invention will be explained in detail with reference to a turbomolecular vacuum pump. Among others, the rotor of a turbomolecular vacuum pump consists of a shaft on which a motor rotor and a pump rotor are rigidly mounted. Further, the shaft may be provided with rotor-side components of the magnet bearing, for instance, permanent magnetic sleeves, rings, etc.
On the stator side, a pump stator, a motor stator and stator-side components of the magnet bearing are provided among others. The stator-side compo-nents of the magnetic bearing include, among others, a plurality of electro-magnets controlled by a magnet bearing control. Moreover, rotor-position sen-sors are provided on the stator side that are adapted to determine the exact position of the rotor at a high measuring frequency and with high accuracy.
When the rotor is at a standstill, a stationary test run is performed prior to the first start-up as well as at regular intervals before powering the rotor up to its operating rotational frequency. Here, the electromagnets of the magnetic bearing maintain the rotor in a floating operating position and is subjected to mechanical oscillations. Thus, the magnetic bearing generates rotor oscilla-tions over a frequency spectrum in which a resonant frequency or a plurality of resonant frequencies specific to the structure or the model of the vacuum pump are expected.
The rotor-position sensors determine whether the rotor oscillations of the re-spective oscillation frequency generated by the electromagnets of the mag-netic bearing build up or not.
In this manner, the resonant frequency of the rotor, which may also change over the operation cycle, can be determined at any time with high accuracy.
For the operation of the rotor, relatively narrow frequency bands can be pro-vided as a safety margin around the detected resonant frequency of the rotor.
The rotor or the turbomolecular vacuum pump can thus be operated at rota-tional frequencies which are, if desired, relative close to a resonant frequency determined in this manner. To be able to operate the turbomolecular vacuum pump in the supercritical rotational frequency range, i.e. in a rotational fre-quency range above a resonant frequency, the region around the resonant frequency must be swept as quickly as possible. Also for the powering up of a vacuum pump to a supercritical rotational speed frequency, an exact informa-tion about the resonant frequency of the rotor is of great importance.
Possibly, the maximum rotational frequency can be selected as close as possi-ble below the resonant frequency of the rotor. The exact determination of the resonant frequency allows to select an operating rotational frequency that may be higher than and thus closer to a resonant frequency than would be possible if the item variation of the resonant frequency were not known. Thus, the maximum rotational frequency of a turbomolecular vacuum pump can be in-creased by up to 10% - 15%.
Claims (6)
1. A method for the determination of resonant frequencies of a rotor using magnetic bearings, comprising the following steps:
- generating mechanical oscillations of the rotor by electromag-nets of the magnetic bearing, - detecting the rotor oscillations by means of rotor-position sen-sors of the magnetic bearing, and - determining the resonant frequencies of the rotor from the de-tected oscillations.
- generating mechanical oscillations of the rotor by electromag-nets of the magnetic bearing, - detecting the rotor oscillations by means of rotor-position sen-sors of the magnetic bearing, and - determining the resonant frequencies of the rotor from the de-tected oscillations.
2. The method of claim 1, characterized in that the frequencies of the os-cillations generated range at least partly above the rotational frequency of the rotor.
3. The method of claim 1 or 2, characterized in that, during the generation of the oscillations, the rotational frequency of the rotor is less than 70%, preferably less than 30%, of the rated rotational frequency of the rotor.
4. The method of one of claims 1-3, characterized in that mechanical oscil-lations of various oscillation frequencies are generated.
5. The method of claim 4, characterized in that mechanical oscillations of various oscillation frequencies of a frequency spectrum are generated.
6. The method of one of claims 1-5, characterized in that the rotor using magnetic bearings is a rotor of a turbomolecular vacuum pump.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102007001201.4 | 2007-01-05 | ||
| DE102007001201A DE102007001201A1 (en) | 2007-01-05 | 2007-01-05 | Method for determining resonance frequencies of a magnetically levitated rotor |
| PCT/EP2008/050043 WO2008081030A1 (en) | 2007-01-05 | 2008-01-03 | Method for determination of resonant frequencies of a rotor using magnetic bearings |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2674263A1 true CA2674263A1 (en) | 2008-07-10 |
Family
ID=39301082
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002674263A Abandoned CA2674263A1 (en) | 2007-01-05 | 2008-01-03 | Method for determination of resonant frequencies of a rotor using magnetic bearings |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US20100072845A1 (en) |
| EP (1) | EP2106505A1 (en) |
| JP (1) | JP2010515004A (en) |
| KR (1) | KR20090098914A (en) |
| CN (1) | CN101583799A (en) |
| CA (1) | CA2674263A1 (en) |
| DE (1) | DE102007001201A1 (en) |
| RU (1) | RU2009129879A (en) |
| WO (1) | WO2008081030A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103196672B (en) * | 2013-03-01 | 2015-07-01 | 北京中科科仪股份有限公司 | Magnetic levitation molecular pump radical protective bearing detection method |
| CN103994889B (en) * | 2014-05-27 | 2016-12-07 | 南京航空航天大学 | A kind of rolling bearing fault detection platform based on electromagnetic excitation and detection method thereof |
| CN106969893B (en) * | 2017-05-26 | 2024-02-20 | 成都中科卓尔智能科技集团有限公司 | Non-contact member rigidity detection equipment and method |
| US11047387B2 (en) * | 2017-09-27 | 2021-06-29 | Johnson Controls Technology Company | Rotor for a compressor |
| CN108429405B (en) * | 2018-01-26 | 2020-02-18 | 瑞声科技（南京）有限公司 | Method and device for detecting resonant frequency of linear motor |
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| US5258923A (en) * | 1987-07-22 | 1993-11-02 | General Electric Company | System and method for detecting the occurrence, location and depth of cracks in turbine-generator rotors |
| JPH01116318A (en) * | 1987-10-28 | 1989-05-09 | Natl Aerospace Lab | Positively acting magnetic bearing |
| JP3090977B2 (en) * | 1991-05-31 | 2000-09-25 | 株式会社日立製作所 | Method and apparatus for controlling magnetic bearing |
| DE69319004T2 (en) * | 1992-03-09 | 1998-12-24 | Hitachi Ltd | Method and device for controlling a magnetic bearing |
| EP0744017B1 (en) * | 1994-04-05 | 2000-02-09 | Monitoring Technology Corporation | Noninvasive method and apparatus for determining resonance information for rotating machinery components and for anticipating component failure from changes therein |
| JPH08121477A (en) | 1994-10-24 | 1996-05-14 | Seiko Seiki Co Ltd | Control device for magnetic bearing |
| JP3083242B2 (en) * | 1995-04-27 | 2000-09-04 | 核燃料サイクル開発機構 | Vibration evaluation method of rotating body in static field |
| US5663894A (en) * | 1995-09-06 | 1997-09-02 | Ford Global Technologies, Inc. | System and method for machining process characterization using mechanical signature analysis |
| US5818137A (en) * | 1995-10-26 | 1998-10-06 | Satcon Technology, Inc. | Integrated magnetic levitation and rotation system |
| WO1997023728A1 (en) * | 1995-12-25 | 1997-07-03 | Muneaki Takara | Electromagnetic piston engine |
| JP3114085B2 (en) * | 1996-01-31 | 2000-12-04 | セイコー精機株式会社 | Magnetic bearing device with radial position correcting electromagnet |
| DE19619997A1 (en) * | 1996-05-17 | 1997-11-20 | Karlsruhe Forschzent | Balancing method for superconducting magnet located rotor mass |
| JP3109023B2 (en) * | 1996-07-18 | 2000-11-13 | セイコー精機株式会社 | Magnetic bearing device |
| DE19828498C2 (en) * | 1998-06-26 | 2001-07-05 | Fraunhofer Ges Forschung | Method for measuring unbalance of rotating bodies and device for carrying out the method |
| DE20021970U1 (en) * | 2000-12-30 | 2001-04-05 | Igus Ingenieurgemeinschaft Umw | Device for monitoring the condition of rotor blades on wind turbines |
| JP2004286045A (en) | 2003-03-19 | 2004-10-14 | Boc Edwards Kk | Magnetic bearing device, and pump unit mounting the same magnetic bearing device |
-
2007
- 2007-01-05 DE DE102007001201A patent/DE102007001201A1/en not_active Withdrawn
-
2008
- 2008-01-03 WO PCT/EP2008/050043 patent/WO2008081030A1/en active Application Filing
- 2008-01-03 CN CNA200880001758XA patent/CN101583799A/en active Pending
- 2008-01-03 JP JP2009544411A patent/JP2010515004A/en active Pending
- 2008-01-03 EP EP08701225A patent/EP2106505A1/en not_active Withdrawn
- 2008-01-03 US US12/522,054 patent/US20100072845A1/en not_active Abandoned
- 2008-01-03 CA CA002674263A patent/CA2674263A1/en not_active Abandoned
- 2008-01-03 RU RU2009129879/06A patent/RU2009129879A/en not_active Application Discontinuation
- 2008-01-03 KR KR1020097016155A patent/KR20090098914A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| EP2106505A1 (en) | 2009-10-07 |
| KR20090098914A (en) | 2009-09-17 |
| DE102007001201A1 (en) | 2008-07-10 |
| JP2010515004A (en) | 2010-05-06 |
| WO2008081030A1 (en) | 2008-07-10 |
| RU2009129879A (en) | 2011-02-10 |
| CN101583799A (en) | 2009-11-18 |
| US20100072845A1 (en) | 2010-03-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |